The overall objectives of this project continue to be the elucidation of how such myogenic factors as slow wave activity and intercellular coupling function to coordinate the activities of smooth muscle. During the current year we will study: (1) The changes in slow wave activity responsible for waxing and waning zones and aborally decreasing slow wave frequency; (2) The effects of electrical stimulation on certain properties of slow waves such as propagation velocity and refractory period; (3) The effects of certain hormones on electrical coupling, measured as junctional impedance, of the myometrium and intestinal smooth muscle; (4) the electrical properties of isolated visceral smooth muscle cells. BIBLIOGRAPHIC REFERENCES: Bortoff, A. and R. Muller. Stimulation of intestinal smooth muscle by atropine, procaine and tetrodotoxin. Am. J. Physiol. 229-1609-1613 (1975). Bortoff, A. Myogenic control of intestinal motility. Physiol. Rev. 56:418-434 (1976).